High speed tape reader mechanism



gApril 21, 1959 R. M. BRINK HIGH SPEED TAPE READER MECHANISM 2 Sheets-Sheet 1 Filed May 22, 1953 April 21, 1959 R. M. BRINK HIGHSPEED TAPE READER MECHANISM 2 Sheets-Sheet 2 Filed May 22, 1953 FIG. 3 90a\ INVENTOR.

ROBERT M. BRINK ATTORNEYS United` States Patent HIGH SPEED TAPE READER MECHANISM Robert M. Brink, New Canaan, Conn., assignor to Time,

icrirporated, New York, N.Y., a corporation of New Application May 22, 1953, Serial No. 356,771

9 Claims. i (Cl. 271-Z.4)

This invention relates generally to the art of motion control mechanisms adapted to produce intermittent states of dwell and high speed motion for an elongated strip of material, and more particularly to the art of motion control mechanisms adapted to produce the aforei tain period of time (which may be called a time lag) is always required for the transition of the condition of the strip from a state of rest to a state of motion or the reverse. This time lag, which represents a non-utilizable ytheexpense of the utilizable portion of the same. `The time lag between the states of dwell and motion of a strip thus determines the highest frequency of alternation at which a motion control mechanism can be employed.

ln the prior art, `motion control mechanisms are known which may be adapted to produce alternate dwell and high speed motion states for a strip of elongated material. In these devices, however, the control over the motion of the strip is exerted by a positive drive, such as for example a sprocket wheel w-hich engages holes in the strip, or a driven roll which frictionally contacts the strip in a non-slipping manner. Accordingly, in the prior art devices the mass involved which must be accelerated and decelerated is the relatively large mass of the member which contacts the strip, `together with the mass of the' `arrangement which drives the member.

such positive drive systems are characterized by long time As a result,

lags limiting them to low frequencies of alternation. A limitation of this sort may be extremely disadvantageous where the strip `and motion control mechanismare associated with a utilization device which canotherwise respond at a much more rapid rate.

it is an object of the invention, accordingly, to remedy the above noted deficiencies in the prior art.

Another object of the invention is to provide new and improved mechanism for producing rapidly alternating motion and dwell states for a strip of elongated material in which the only mass which determines the time lag of the strip between states is that of the strip itself.

A further object of the invention is to provide for firm grasping of the strip when arrested from motion.

A still further object of the invention is to provide a yieldable strip driving `force to guard against tearing of the strip when rapidly decelerated. t

According to the invention, an elongated strip of material, as for example an indicia bearing, magnetic tape 1s urged to motion by a driving mechanism which exerts a V ICC continuous but yieldable driving force on a portion ofthe strip. Ahead of the driving mechanism is located a` pair of jaw members which may be selectively closed or opened to grasp orrelease, respectively, another portion of the strip. When the jaws are closed, the grasping action of the same is suflicientto overcome the driving force on the strip imparted thereto by the driving means with the result that the strip remains stationary in a state of dwell. intermittently, however, the jaws areopened by an actuator, for example a solenoid, with the result that the strip rst rapidly accelerates to a stat-e of high speed motion, and then, upon subsequent deenergization of the actuator, the strip is rapidly decelerated to return to the dwell state. In the course of the transition from one state to another, the only mass which determines the time lag of the strip is that of the strip itself, with the result that the time lag is minimized and the frequency of alternation between states which may be employed is maximized.

For a better understanding of the invention, reference is made to the accompanying detailed description of a representative embodiment as shown in the figures of the accompanying drawing in which: f

Figure l is a diagram in perspective of the motion control mechanism `and the elongated strip of material moved thereby;

Figure 2 is a schematic diagram of an apparatus with `which the motion control mechanism is associated;

Figure 3 is a fragmentary view of a narrow magnetic tape with indicia groups therein extending along the tape length;

Figure 4 is a'sectional view of another form of mechanism for imparting driving force to the tape; and

Figure 5 represents in sectional view yet another form of force imparting mechanism.

Referring now to Figure l, a strip of elongated material, in the present instance, shown as a length of magnetic tape anddesignated by the number 10 passes between two oppositely disposed longitudinally extending sections 12 and 13 of a pair of continuous fabric belts 14 and l5, respectively. The length and position of section 12 is formed by passing belt 14 over and around a driving roll 16 and an idler roll 17, both of which rolls are supported as described below by a base 18 which also acts as the support for the other major elements of the tape control mechanism.

The driving roll 16 is rigidly mounted on a transverse shaft 19 having opposite ends thereof journalled in a pair of supporting standards Ztl (only one of which is shown) upon the base 18. Similarly the idler roll 17` is mounted on a transverse shaft 23 having opposite ends journalled in standards 24 and 25. The position of the standards 24 and 25 upon the base 18 may be adjusted by set screws 2o.

driven Vby a belt 31 driven in turn by a driving pulley32 carried by a drive shaft 33 journalled in standards 34 and 35 on the base 18. The shaft 33 is driven through conventionalfcoupling 36 by a constant speed motor 37, as

for example a synchronous motor.

In a similar manner, the longitudinally extending section 13 of :belt 15 is formed by the passing of the fabric i The shaft 19 is provided with a pulley 38 which is 3 means of set screws-47 and 47a in slots 48, 48a, respec tively.

The shaft 41 is driven by a pulley 49 and belt 50 from a pulley 51 driven by the drive shaft 33. Accordingly, each of the sections 12 and 13 of belts 14 and 15 will be givena motion in the same longitudinal direction, as shownby the arrows of Figure l.

The upper plate 40 is adjustable in displacement from base 18 by a pair of standards 52 (one not shown) upstanding from Ibase 18 and a corresponding pair of standards 53 (one not shown) downstanding from plate Each of thestandards 52 is fastened to its corresponding standard 53 by a pair of set screws 54, 54a passing through vertical slots in the two standards. By adjusting the spacing of upper roll plate 40 from base 18, by loosening and retightening the set screws the frictional force exerted |by sections 12 and 13 upon tape 10 can be brought to any desired value. As sections 12 and 13 move in the direction shown by the arrows of Figure l, the frictional engagement of the sections with the portion of the tapewhich they contact, imparts to that portion, Iand consequently to the length of the tape following, a constant tangential drive force which urges the tape to motion in the direction of the arrows, and which, when the tape is unrestrained, causes motion of the same. The magnitude of this tangential drive force is held 'by proper spacing between upper roll plate 40 and base 18 to a value sufliciently moderate so that when the tape is elsewhere firmly grasped, first, the motion of the tape 10 is arrested without any damage resulting to the tape from the moving belts and, second, the belts 14 and 15 are substantially unaffected by the fbraking action of the stopped tape, continuing, therefore, to move at their usual speed.

The -use of the linearly extended sections of 12 and 13 has the advantage that the tape when arrested does not bind to the drive surface, thus unduly amplifying the drive force imparted to the tape.

In order to assure continuous frictional engagement between sections 12 `and 13 and tape 10 for the whole area of the sections, a pair of arms 55 (one not shown) hinged on shaft 44 are joined together at their free ends by a pin 56 carrying in freely rotatable relation 'an idler roll 57. The arms 55 are spring biased by a pair of coil springs 58 (one not shown) so that the idler roll 5'7v is urged downwardly against -belt 15. As a consequence, sections 12, 13 and the portion of tape 10 included therebetween assume a slight downwardly curved shape which increases frictional engagement between the tape and the sections.

Referring now to the means by which magnetic tape 10 may be restrained from motion, spaced away from sections 12, 13 in a direction opposite that of tape motion are ia pair of jaws 60, 61 containing another portion of the tape 10. Preferably, jaw 60 is a fixed jaw mounted upon `base 18 and having for a jaw face a iiate smooth upper surface. The other movable jaw 61 consists of 4a cross arm 62, a sleeve 63 which is freely pivotable about a transverse pivot pin ,64, and a connecting arm 65 which joins cross arm 62 to sleeve 63. The cross arm 62 has a flat lower surface covered with a semi-yieldable material (c g., rubber) to provide a frictional surface, which is adapted to cooperate with the jaw face of fixed jaw 60 to grasp a portion of the tape between the two jaw faces.

Intermittently, movable jaw 61 is adapted to be separated from fixed jaw 60 by means of the coupling rod 67 which is joined at one end to a median portion of connecting arm 65, and at the other end to the armature of an actuating solenoid 68. When solenoid 68 is energized so that current iiows in its coil, the armature of the sole noid is drawn towards the center of the coil, and coupling rod 67 lifts cross arm 62 away from fixed jaw 60 to red lease the tape 10. Upon deenergization of solenoid 68, under the urging of a pair of springs 69 connected between cross arm 62 and fixed jaw 60, the movable jaw 61 will be drawn to fixed iaw 60 to grasp the tape 10 between thev two jaw faces.

It will be noted that the pivot pin 64, about which movable jaw 61 pivots is spaced away from the tape in a longitudinal direction between the fixed jaw 60 and the fabric belts 14, 15. As a result of the positioning of the pivot pin 64, once jaws 60 and 61 are driven together under the urging of springs 69, the driving force imparted to the tape 10 from sections 12, 13 will draw arm 62 even more tightly down against the fixed jaw 60. Consequently, restraint of the tape upon closure of the jaws is always assured regardless `of the amount of driving force imparted to the tape from belts 14, 15 or the strength of springs 69.

In Figure 1 `a pair of idler and driver feed rolls 71, 72 anda pair of idler 'and driver feed rolls 73, 74, respectively advance the tape to form a partial loop 75 and draw the tape away from a partial loop 76. From Figure 1 it is Iapparent that the loops 75, 76 form temporary tape storage regions which isolate the start-stop motion of the limited extent of tape 10 Ibetween the loops from the remainder of the tape, `located in part to the left of rolls 71, 72 and in part to the right of rolls 73, 74. It is to be noted that during start-stop motion, the only mass which needs must be accelerated or decelerated by the fabric belt tape drive is the mass of the tape portion lying between the loops, =and to a lesser` extent the mass of the loop portions of the tape.

Tape 10 carries in longitudinally spaced relation a number of transverse code groups of indicia and a number of indicia 81 marking the position of each code group. The various indicia 80 in each code group are separately scanned by a set of pick-ups 83a-83e (Fig.

2) inclusive mounted upon a pick-up head 84. Similarly the indicia 481 are scanned by a pick-up 85 on the head 84. In order to maintain proper contact between the tape and the pick-up, tape 10 is fed past a fixed guide bar 86 preceding the head 84 and past another fixed guide bar 88 following head 84.

Referring now to Figure 2, the block designated represents an electronic photocomposer as disclosed in the application of Battle Klyce and F. Kim-ball Loomis, Serial No. 343,116, filed March 18, 1953, for Photocomposing Mechanism. The photocomposer 100 is adapted, responsive to different code groups of indicia 80, to automatically perform operations associated with 'a printing apparatus, as, for example, the printing of characters on a carrier medium, the spacing of these char acter as printed, 'the creation of word spaces, and the shifting of the material `being printed to a new line or column.

Assume now that one of these mentioned operations has just been performed by thephotocomposer 100. in such case the tape 10 will be in 'a state of high speed motion, in Ia direction coming out of the surface of the figure as shown in Figure 2. This motion continues until a new code group, signified by a given row of indicia 80 in the tape 10, is swept past the pick-up head 84. At such time the information carried by thevarious indicia 80 is converted into a corresponding group of electric signals by the change in magnetic flux experienced by the pick-ups 83a-83e inclusive `as the indicia 80 move past them. Simultaneously, the indicium 81 is swept past the pick-up 85 to produce another electric signal, which, after a short delay by passage through a delay circuit 101, is applied to la multivibrator 102. The multivibrator 102, which is of a conventional bistable type, is normally conditioned to supply a positive signal to the grid 103 of ya triode 104. Upon receiving the signal from delay circuit 101, the multivibrator 102 reverses its conductivity states to drive grid 103 negative with the result that tube 104 is cut oif.

The plate cathode path of tube 104 is connected in a loop circuit with the coil 106 of solenoid 68 anda source of operating voltage :and current (not shown). Normally current flows through coil 106 to maintain the armature 107 of the solenoid 6,8 in the center of the coil, solenoid when thus energized maintaining, through `coupling essere? an indiciurn` 31 sweeps pastt-pick-up 85, the `tape 10 is n caused to assume a state of dwell.` v

Upon completion of one of its mentioned operations, the photocomposer 100 produces a second signal which also is applied to the multivibrator 102` to again reverse the state of the same. Multivibrator 102, thereupon, again applies Ia positive signal to the -grid 103 of the `tube 104, and solenoid l68 is reenergized` to cause a ,corresponding release of tape by jaws 60 and 61. Upon being released tape 10 rapidly accelerates to a state .of` high speed motion, in which `state it continues until another code group of indicia `80 4and lan indicium 81 sweeps past the pick-ups,` at which timethe` cycle just-described repeats itself. i t

The tape driving mechanism described may also be employed where (as shown inFigS) separate code groups of indicia 80a of either positive or negative `polarity are disposed along the length of a narrow magnetic tape 10a... In such ease only a single pick-up 85a need be utilized,.the pick-up 85a generating a sequence of signals as thevarious indicia 8l)` in larcode group sweeppast the same. Upon the scan of la full code group by thesingle j pick-up, an electric signal is supplied from, for example, indicia counting means (not shown) to the multivibrator 102 to cause arrest of the tape motion as described.

Figure 4 shows a form of tape driving `mechanism advantageous in that only the indicia-free (upper) side of the magnetic tape is frictionallyA contacted, thus eliminating wear on the magnetic signal sensitive coating.` The illustration of Figure 4 represents a sectional view ltaken through the axis `of axroll 39b (identifiable withroll 39 t of Fig. 1) and looking in thedirection of tape motion.

-Roll 39b,iwhich is supported by a shaft 44h carries (in conjunction with anotherroll;` not shown), `a fabric 'belt 15b in Ia manner similar to that shown for fabric belt 15 (Fig. l). The belt 15b has a lower straightaway sec-t tion extending rearwards of the` drawing plane in Figure 4, this section being adapted by frictionalengagement to `impart a` continuous driving force to a narrow tape 10b of the type :shown in Figure 3tape '10b being 4adapted to carry indiciaon the lowerside thereof.

For maintenance of continued frictional contact between belt 15b and tape 10b, a blower box 110 is disposed below the tape 10b; `The blower boxllt) has formed in the interior thereofan 'air chamber 111 and on the upper 4surface thereof a hemi-cylindrical` groove 112 aligned and coextensive with the 'straightaway sectionfof belt 15b. Air chamber 111 communicates with groove 112 by means of a narrow slot 113 running (rearward from the drawing plane in Fig. 4) the full length of the groove.

In operation air chamber 111.by means of a port 114 Vreceives compressed air from an air supply (not shown). The air so received is forced from chamber 111 through slot 113 to raise the air pressure in` the space included `within groove 112. The increased air pressure in this space acts to blow tape`10b with constant force against the straightaway section of belt 15b. A small clearance between the upper surface of blower box 110 and tape 10b (when in contact with belt 15b) permits air leakage to assurea `constant air iiow through the blower box.

Figure 5 shows in sectional View a mechanism` involv- Aing no frictional force, for imparting a continuous driving foi-certo a magnetic tape.V In the figure, a narrow tape 10c of the type shown in Figure 3 is fed past-a fixed guide Aarea of an extended portion of the tape.

thetape width. Tape 10c is `led into and out of the vacuum box through slits 122 and 123 permitting only slight tape clearance. .Both slits 121 and 122 have faired approaches for either direction of approach `to the slits. w

Between slits 1,22 and 123 the tape 10c forms a partial `port 124.

The vacuum so created tends to pull tape 10c from the left to form a continuously larger loop 76C. Loop 76C, however, is monitored for `size by a photosensitive device 125 (identifiable with device 77 lof Fig. l) so that when the bottom of loop 76C drops below the level of device 125, tape 10c is drawn to the right and out of the vacuum box 12,0 by cooperating idler and driver rolls 73a and 74a (identifiable with rolls 73 and '74 of Fig. l), driver roll 74a being limited by conventional means (not shown) to rotate only in its appropriate feed direction, The movement of roll 74a is controlled by device 125 in the mode previously described with respect to photo- `sensitive device 77' and roll 74 (Fig. l).

.lt is apparent, therefore, that a continuousforce urging tape 10c rightwards is exerted by the vacuum in vacuum box 120. At the same time, whenever loop 'fdc in the vacuum box becomes too` large the `tape 10c is advanced out of the vacuum box to re-establish the proper size for the loop.

It will be noted that the tape driving mechanisms of Figures l, t and 5 are commonly related in that each distributes the driving force imparted to the tape over the Such force distribution is advantageous in that it permits impartment of an effective driving force to the tape while at the same time causing distribution over the mentioned area of the stress set up in the tape upon being arrested from motion. v The invention thus provides a novel and. highly effective motion control mechanismfor producing alternating states of motion anddwell in a strip` of elongated material, as, for example, a magnetic tape. By imparting a `continuous drive force tothe strip and by intermittently arresting the motion of the tape by grasping another portion thereof with a pair of jaws, the time lag required for travel between a state of dwell and a state of high speed motion, or the reverse, can be minimized. Moreover, as a result of the particular jaw structure employed, the jaws when once closed become self-holding, thus rendering the mechanism independent of variations in the drive force imparted to the tape or the force which initially draws the jaws together. Moreover, the motion control mechanism may `be gainfully employed with a record controlled utilization device in which the tape is advanced after completion of each operation bythe device and is stopped each time the device picks up a signal corresponding to a new group of indicia.

The embodiments shown in the drawings and described herein are obviously susceptible to considerable modilication in form and detail within the spirit of the inven-l tion. The embodiments, therefore, are to be regarded as illustrative only and not as limiting the scope of the following claims.

I claim:

l. ln a utilization device adapted to perform a set of operations separately initiated by the scanning of correv sponding separate indicia spaced along an elongated magnetic tape, said device producing rst and second signals respectively upon `completion of each operation and upon scanning of a particularly characterized indicium, in combination with said device, distributed force drive means adapted to impart over the area of a lengthwise extending unwrapped portion of said tape a continuous pulling 2,saa,1 sv

force urging motion thereof, a pair of jaws adapted for selectively freeing and restraininganother pulled portion of said tape to correspondingly vpermit and arrest said motion, and means responsive to said Vrst and second signals, respectively, for rendering said pair of jaws selectively operative to free and to restrain said other portion.

2. In a utilization device adapted to perform a set of operations separately initiated by the scanning of corresponding separate indiciaspaced along an elongated magnetic tape, said device producing first and second signals respectively uponl completion of each-operation and upon scanning of a particularly characterized indicium, in cornbination with said device, distributed force drive means adapted to impart over the area of a lengthwise extending unwrapped portion of said tape a continuous pulling force urging motion thereof, a pair of jaws adapted for selectively freeing and restraining another pulled portion of said tape by mutual separation and closure of sm'd jaws, respectively, to correspondingly permit and arrest said motion, means responsive to said first and second signals,

respectively, for separating and iclosing said jaws, andv means responsive to said force as exerted by said tape upon said jaws when in closed position for holding said jaws in closed position.

3. In a utilization device adapted to perform a set of operations separately initiated by the scanning of corresponding separate indicia spaced along an elongated magnetic tape, said device producing first and second signals respectively upon completion of each operation and upon scanning of a particularly characterized indicium, in combination with said device, distributed force drive means adapted to impart over the area of a lengthwise extending unvvrapped portion of said tape a continuous force urging motion thereof, a fixed jaw and a pivoted jaw mutually adapted to selectively free and restrain another portion of said tapev respectively upon movement of said pivoted jaw to open and closed positions respectively with reference to said fixed jaw, said jaws by freeing and restraining said other portion correspondingly permitting and arresting said motion, a pivot for rendering said pivoted jaw movable to said open and closed positions, said pivot being disposed at a location fixedly spaced normal to said tape and longitudinally between said fixed jaw and said means on the same side of said tape as said pivoted jaw, said pivot location and said force on said tape conjointly rendering said pivoted jaw self-holding in said closed position, and means responsive to said first and second signals for correspondingly moving said pivoted jaw to said open and closed positions.

4. Apparatus in which a magnetic tape is adapted for signal transfer purposes to be intermittently moved in a predetermined direction in a predetermined path, said -ap-' posed between first and second parts of said path in which l said tape is adapted to form respective first and second slack loops, said first path part, path length and second path part being disposed in the order named in said direction, a magnetic signal transfer head disposed along the extent of said path at a mediate position in said path length to provide for signal transfer between said head and said tape when said tape moves past said head, tape drive means disposed at a position along the extent of said path between said head and the far end of said second slack loop, said drive means being adapted by a yieldable cooperation with an unwrapped portion of said tape at said last named position to impart to said unwrapped portion a continuous drive force exerted in said direction and trans' and said first slack loop, said jaws being adapted by alternately opening from each other and closing towards each other to alternately release said tape and to grasp said tape by said faces-with 'a1/restraining force exceeding said drive force, said'jaws being thereby adapted'to impart a startstop motion to a portion ofsaid tape extending out of said rst slack'loop through said-path length and into said second slack loop.

5. Apparatus as in claim 4 in which at least one of said jaws is adapted to relatively open and close with the other jaw by movement of said one jaw about a pivot, and in 'which said pivot isl at a location which is spaced normally of said tape on the same side of said tape as said one jaw, and which is offset in'said direction from the place where said jaw faces are adapted to grasp said tape, said one jaw thereby being adapted to be held in closed position by the drive force transmitted through said tape when said j jaw faces arev closed thereon.

6. Apparatus in which a magnetic tape is adapted for signal transfer purposes to be intermittently moved in a predetermined direction in a predetermined path, said ap.- paratus comprising, tape guide means establishing a configuration for said path in which a length thereof is disposed between first and second parts of said path in which said tape is adapted to form respective first and second slack loops, said first path part, path length and second path part being disposed in the order named in said direction, a magnetic signal transfer head disposed along ythe extent of said path at a mediate position in said path length to provide for signal transfer between said head and -said tape when said tape moves past said head, at least one continuous belt having a linearly-extended tapedriving surface tangential to said path at a position between said head and said second slack loop, said driving surface being adapted to be continuously urged to movement in said direction along said path, means to maintain an unwrapped portion of said tape at said last named position `in yieldable frictional cooperation with said drive surface, whereby said drive surface is adapted to impart to saidLunwrapped portion a continuous drive force exerted in said direction and transmitted from said unwrapped portion through said tape in said length of path to continuously urge said motion of said tape out of said first slack loop, past said head, and into said second slack loop, a pair of jaws 4having cooperating faces and disposed along the extent of said path on opposite sides of said tape at a position between said vhead and said first slack loop, said jaws being adapted by alternately opening from each other and closing towards each other to alternately release said tape and to grasp said tape by said faces with a restraining force exceeding said drive force, said jaws being thereby adapted to impart a start-stop motion to a portion of said tape extending out of said first slack loop through said path length and into said second slack loop, and belt drive means to continuously urge said belt drive surface to said movement thereof by a force exceeding said drive force, whereby said surface continuously moves but is adapted to slip relative to said tape when said tape is grasped by Vsaid jaws.

7. Apparatus in which a magnetic tape is adapted for signal transfer purposes to be intermittently moved in a predetermined direction in a predetermined path, said apparatus comprising, tape guide means establishing a `configuration for said path in which a length thereof is disposed between first `and second parts of said path in which said tape is adapted to form respective first and second slack loops, said first path part, path length and second path part being disposed in the order named in said direction, a magnetic'signal transfer headdisposed along the extent of said path at a mediate position in said path length to provide for signal transfer between said head and said tape when said tape moves past said head, a pair of continuous belts having respective linearly-extended tape-driving surfaces opposite eachother and on opposite sides of said tape at a position along the extent of said length of .path between said head and said second slack loop, each of said surfaces being adapted to be continuously urged to movement in said direction along said path, and said surfaces being adapted to be in yieldable frictional cooperation with opposite sides of an unwrapped portion of said tape at said last named position to impart to said unwrapped portion a continuous drive force exerted in said direction and transmitted from said unwrapped portion through said tape in said length of path to continuously urge said motion of said tape out of said rst slack loop, past said head, and into said second slack loop, a pair of jaws having cooperating faces and disposed along the extent of said path on opposite sides of said tape at a position between said head and said first slack loop, said jaws being adapted by alternately opening from each other and closing towards each other to alternately release said tape and to grasp said tape by said faces with a restraining force exceeding said drive force, said jaws being thereby adapted to impart a start-stop motion to a portion of said tape extending out of said rst slack loop through said path length and into second slack loop, and belt drive means to urge each of said belt surfaces to said movements thereof by a force exceeding said drive force, whereby said surfaces move but are adapted to slip relative to said tape when said tape is grasped by said jaws.

8. Apparatus in which a magnetic tape is adapted for signal transfer purposes to be intermittently moved in a predetermined direction in a predetermined path, said apparatus comprising, tape guide means establishing a configuration for said path in which a length thereof is disposed between first and second parts of said path in which said tape is adapted to form respective rst and second slack loops, said iirst path part, path length and second path part being disposed in the order named in said direction, a magnetic signal transfer head disposed along the extent of said path at a mediate position in said path length to provide for signal transfer between said head and said tape when said tape moves past said head, at least one continuous belt having a linearlyextended tape driving surface tangential to said path at a position between said head and said second slack loop, said driving surface being adapted to be continuously urged to movement in said direction along said path, pneumatic means adapted by generating a ow of air to produce on an unwrapped portion of said tape at said last named position an air pressure which is greater on the side of said portion away from said surface than on the side of said portion towards said surface to thereby maintain said unwrapped portion in yieldable frictional cooperation with said drive surface, whereby said drive surface is adapted to impart to said unwrapped portion a continuous drive force exerted in said direction and transmitted from said unwrapped portion through said tape in said length of path to continuously urge said motion of said tape out of said first slack loop, past said head, and into said second slack loop, a pair of jaws having cooperating faces and disposed along the extent of said path on opposite sides of said tape at a position between said head and said rst slack loop, said jaws being adapted by alternately opening from each other and closing towards each other to alternately release said tape and to grasp said tape by said faces with a restraining force exceeding said drive force, said jaws being thereby adapted to impart a start-stop motion to a portion of said tape extending out of said rst slack loop through said path length and into said second slack loop, and belt drive means to continuously urge said belt drive surface to said movement thereof by a force exceeding said drive force, whereby said surface continuously moves 7 but is adapted to slip relative to said tape when said tape is grasped by said jaws.

9. Apparatus in which a magnetic tape is adapted for signal transfer purposes to be intermittently moved in a predetermined direction in a predetermined path, said apparatus comprising, tape guide means establishing a configuration for said path in which a length. thereof is disposed between rst and second parts of said path in which said tape is adapted to form respective lirst and second slack loops, said rst path part, path length and second path part being disposed in the order named in said direction, a magnetic signal transfer head disposed along the extent of said path at a mediate position in said path length to provide for signal transfer between said head and said tape when said tape moves past said head, means to restrain said tape from being drawn into said second slack loop from the side thereof away from said path length, pneumatic means to produce on the inner side of said second slack loop a cushion of air at a pressure which is continuously greater than that of the air in the region on the outer side of said last named loop to thereby tend to continuously enlarge said second slack loop, said air cushion being adapted to yieldably cooperate with an unwrapped portion of said tape in said second slack loop to impart to said unwrapped portion a continuous drive force exerted in said direction and transmitted from said unwrapped portion through said tape in said length of path to continuously urge said motion of said tape out of said first slack loop, past said head, and into said second slack loop, a pair of jaws having cooperating faces and disposed along the extent of said path on opposite sides of said tape at a position between said head and said first slack loop, said jaws being adapted by `alternately opening from each other and closing towards each other to alternately release said tape and to grasp said tape by said faces with a restraining force exceeding said drive force, said jaws being thereby adapted to impart a start-stop motion to a portion of said tape extending out of said first slack loop through said path length and into said second slack loop, and means responsive to enlargement of said second slack loop to produce movement of said tape in said direction out of said second slack loop.

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